The Simba Cool Foam Mattress Topper arrived in my life at exactly the right time

RRP at time of testing: from £149 | Check price at Amazon or Simba directly 

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My verdict

The new Simba Cool Foam Mattress Topper arrived in my life at exactly the right time: a heatwave in Leeds, a doubly insulated dormer bedroom and the dawning realisation that my much-loved feather topper was probably not doing my asthma any favours. 

After three weeks of sleeping on it with my husband, I’d say this is a useful mattress topper for hot sleepers or anyone who finds traditional memory foam too claggy. It doesn’t feel icy when you lie down. It isn’t a gel topper, and it won’t perform miracles in a boiling bedroom with no air conditioning. But it did help our bed feel less stifling, more supportive and more temperature-neutral during a very sweaty May. 

Granted, it’s not as luxurious or cosy as a goose down topper like the one we’ve been sleeping on by Soak & Sleep - if you love that puffy hotel-bed feel, Simba’s newest release will take a little getting used to. But if you want a more breathable, allergy-friendly and supportive upgrade, it makes a lot of sense.

How I’ve tested the Simba Cool Foam Mattress Topper

My DH and I slept on the Simba Cool Foam Mattress Topper for three weeks in May, during a ‘warm spell’ in Leeds. At one point, temperatures reached 34°C - which is great when you have air conditioning at home, but we all know not many UK homes are equipped with that. 

We tested the super king size on our own mattress in our dormer master bedroom. Our house is doubly insulated, which is excellent in winter and less excellent when the bedroom starts behaving like a sauna. We frequently sleep with both of our skylights open, the fan on and the downstairs windows open in a pointless attempt to create airflow at night. 

Usually, my husband is the hot sleeper and I’m the cold one. During this testing period, however, we were both sweaty bods. That made it a very useful test for a cooling topper. Was it a glamorous test? No. But thorough? Unfortunately, yes. 

Simba Cool Foam Mattress Topper: what’s in the box?

The topper arrives rolled up and vacuum-packed in a branded Simba cardboard box. There’s no complicated assembly, as you’d expect. Inside the box you get the rolled mattress topper with its removable cover already fitted.

Simba says the topper has elastic straps (it has) and a slim-limiting base, and those are already part of the design rather than separate bits you need to attach yourself. 

We tested a super king size

First impressions and set up of the Simba Cool Foam topper

Coming rolled up quite densely in the box, the topper looked compact at first, particularly for something destined for a super king mattress. I opened it and rolled it out onto our mattress a few hours before bed to give it time to expand. 

It feels like foam. A slab of foam, frankly. That is not an insult, just an honest first impression. If you’re coming from a feather or down topper, as I was, the difference is obvious. There’s no fluffy loft or soft puffiness. Instead, Simba’s cooling option has a flatter, firmer and more functional feel.

That said, it wasn’t uncomfortable. It expanded well, sat neatly on top of the mattress and didn’t involve any wrestling beyond the usual super king bedding faff. The corner straps helped keep it in place and the slip-limiting base gave it a more secure feel once the sheet was on.

Warning, the box is heavier than it looks

Instead, the topper has a layer of Simba’s Simbatex foam over a contoured foam base. To you and me, that means the top layer is designed for cushioning and breathability, while the base adds support and creates small pockets of air to move through. It’s still very much a foam topper, rather than a mini mattress, but the design feels more purposeful than a plain slab of memory foam. 

One practical warming: this topper adds 6.5cm to your mattress depth, which might be a nuisance when you’re trying to find bed sheets that fit. You’ll likely find a standard fitted sheet will struggle when added. Thankfully, we already had extra-deep fitted sheets - so I’d recommend considering these, especially if your existing mattress is already on the deep side. 

What’s it like to sleep on Simba’s Cool Foam topper? 

The Simba Cool Foam Mattress Topper has a medium-firm feel, which I’d say is fairly accurate. It’s cushioned, but not so soft that you sink-in to it like a feather topper. My husband actually preferred it to our previous topper as it gave more support. I can see why, as it holds you up more than it hugs you

I found it took a few nights to adjust. I had spent the previous (albeit colder) months loving our Soak & Sleep goose down dual chamber topper, which has that plush, cosy, nest-like feel. Moving from that to foam was a shift. But, once I stopped expecting it to feel like a featherbed and judged it for what it is, I started to appreciate it.

It arrives rolled up in protective packaging, vacuum packed

It’s responsive, too. Some foam toppers make you feel as though the bed is slowly swallowing you whole. This didn’t. Turning over to sleep on my sides felt easy, and I didn’t get that stuck-inplace sensation you can sometimes get with slower-rebound memory foam. 

I do wonder whether it would feel as supportive over the longer term as Simba’s alternative Hybrid Mattress Topper, which has microsprings as well as foam. The Cool Foam Topper is the more affordable, foam-only option, and that’s worth remembering. If your mattress is fundamentally fine but needs a cooler comfort layer, this works well. But if your mattress is badly sagging, you might want to consider the original Hybrid topper. 

Does the Simba Cool Foam Mattress Topper improve your sleep?

For us, yes, but in a certain way. It didn’t suddenly turn our bedroom into a chilled hotel suite. We still slept in a warm room, and we still had the fan going. We still questioned why British homes are built for retaining heat but surviving summer.

What it did do was make the bed feel more supportive and less heat-trapping. I woke up less aware of that horrible warm patch underneath me, and my husband, who runs hotter than I do, found it more comfortable than our previous feather topper during warm nights. 

It takes a little while to expand and achieve its true shape after unboxing

There was another, slightly unexpected, benefit: I realised the goose feathers in our previous topper were probably causing my asthma to flare up. Lovely inherited genetics from my darling mother. I’d blamed our new dog, obviously, because why blame your own bedding when there’s an innocent animal nearby? Once the lightbulb turned on, switching to foam suddenly made a lot of sense. 

(This is not to hate on the Soak & Sleep topper. I loved it in the cooler months. But for me, with allergies and warmer weather in the mix, Simba’s foam option was better suited to the moment.)

Does the Simba Cool Foam Mattress Topper keep you cool?

This is the big question, and the honest answer is: it helps, but not in the way some people might expect. 

The Simba Cool Foam Mattress Topper does not feel instantly cold when you lie on it. It’s not like a gel pad or the cool side of the pillow. Instead, the Simbatex design is about airflow and breathability. The open-cell foam is infused with graphite, designed to let air move through it more easily and help warmth disperse away from you, rather than trapping body heat underneath you.

During our three-week test, including some very hot nights, we found it helped to keep our temperatures steadier. We weren’t festering under the duvet in quite the same way, and I didn’t wake up feeling as though the topper had absorbed and held onto every bit of body heat like a grudge. 

That said, no mattress topper is going to defeat a doubly insulated dormer bedroom in a heatwave all by itself. If your room is roasting, you will still be warm. This topper is breathable, not magical. 

It was a transition moving from a goose down topper to a memory foam one

Is the Simba Cool Foam Mattress Topper easy to clean?

The top cover is removable and machine-washable at 40°C on a reduced spin cycle. That’s useful, especially if you’re dealing with hot sleepers, pets or children who appear in your bed at 3am.

The foam base itself is spot-clean only, so I would still use a mattress protector. Simba recommends this too, saying it can help extend the life of both your mattress and mattress topper. The cover can’t be tumble dried, ironed, bleached or dry cleaned either - this isn’t a strip-it, wash-it, dry-it-in-an-hour situation. 

For a family home, the washable cover is a definite plus - and something commonly found with Simba products. But it’s worth being realistic: it’s not the same as the entire topper being washable.

Is Simba’s Cool Foam topper good value for money? 

The Simba Cool Foam Mattress Topper starts from £149 for a single, with the super king priced at £299 at the time of writing. A king size is £249. 

That’s not bargain-basement bedding, I’ll admit. You can buy cheaper toppers, and you can also buy much more expensive ones. In Simba terms, though, this is the lower-priced way into the brand’s sleep tech. It sits below the Hybrid Essential Topper and Hybrid Topper, both of which add microsprings and cost more. 

The corner straps keep the topper in place nice and neatly

For me, the value depends on what you need it for. If you want a plush, cosy winter topper, I’d still be tempted by something softer. If you want a breathable, supportive foam topper for warmer weather, hot sleepers or feather-allergy avoidance, it feels like a sensible buy.

The 200-night trial also helps. Mattress toppers are annoyingly personal, and what feels supportive to one person feels like sleeping on a camping mat to another. Being able to try it properly at home is a meaningful benefit. Simba says it will collect the topper free of charge during the trial in most of the UK if it isn’t right for you.

Simba Cool Foam Mattress Topper: can it be recycled?

Simba says it is a B Corp and uses CertiPUR foam, with recycled materials included where possible. The brand also says it offers a Simba-certified recycling and refurbishment service through a trusted third party.

That’s a positive, though I’d still like more detail on exactly what happens to the topper at the end of life and how much of it can be recycled. Foam bedding is not automatically easy to dispose of responsibly, so this is an area where more transparency is always welcome.

One useful environmental point is that a topper can extend the useful life of a mattress that is still structurally sound. If your mattress just feels a bit too firm, too warm or not quite comfortable enough, adding a topper is less wasteful than replacing the whole mattress.

Then again, if your mattress has collapsed into a person-shaped trench, it’s probably time to admit defeat.

Comparison Simba mattress toppers: Cool Foam vs Hybrid Essential vs Hybrid

Final verdict - is this the topper for you? 

The Simba Cool Foam Mattress Topper is a good choice if you sleep hot, dislike the clammy feel of traditional memory foam or want a more supportive alternative to soft feather and down toppers. It’s also worth considering if allergies make natural fillings tricky, or if you want to refresh a mattress without replacing the whole thing.

As ever, our pooch was the first to investigate before I had chance to myself

It is not the topper I’d choose for someone who wants a plush, sink-in hotel-bed feel. It’s also not the answer to a mattress that is sagging, lumpy or long past its best. And if you’re hoping for something that feels cold the second you lie down, this isn’t that. Its cooling is more about breathability and steady temperature regulation than instant chill.

For us, tested over three warm weeks in a stuffy Leeds bedroom, it did exactly what I hoped it would do. It made the bed feel more supportive, less stifling and better suited to summer. Not life-changing. Not useful, which is often the higher praise.

About the author

Rebecca Roberts (aka Beccy) is our resident lifestyle expert with a practical focus on sleep, wellness and everyday comfort. She’s equally at home tackling frank, NSFW‑adjacent topics as she is road‑testing kitchen appliances, mattresses and vacuums that work for real parents. A former editor of LJMU’s Looprevil Press, she cut her teeth in journalism in 2010, earned a post‑grad diploma in Journalism and later led editorial at ExpatWoman in Dubai before joining Mumsnet. As a mum of two, she writes with the time‑poor, sleep‑deprived in mind - honest product reviews, realistic routines and products that make parents’ lives easier.

When she’s not at her desk, she’s probably product‑testing with her two helpers, corralling a PTA or walking her two dogs up and down country lanes.

About Mumsnet reviews

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All prices are correct at the time of writing.

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